Smoke & Fumes — SMOKE/FUMES & AVNCS SMOKE

This article covers the A330's cabin-level smoke / fumes handling — the QRH SMOKE/FUMES/AVNCS SMOKE procedure. It is one of the longest ECAM/QRH procedures (immediate actions + three source branches + ELEC EMER CONFIG), and two of ATA 21's four L3 red life-threat warnings are here (SMOKE/FUMES + AVNCS SMOKE).

1. Two of the four L3 warnings

[!important]- ATA 21's four L3 red warnings

L3 warning	Handling	Article
CAB PR EXCESS CAB ALT	emergency descent	ata-21-24
SMOKE / FUMES	here	this
SMOKE AVNCS VENT SMOKE	here (linked)	this
CARGO SMOKE	the ATA-26 fire procedure	ata-21-27

This article covers two of the four — the core of ATA 21's most dangerous scenario.

2. When to apply — a suspicion or a smell, no ECAM needed

This procedure includes all the steps of the SMOKE AVNCS VENT SMOKE procedure. Apply this procedure when: The flight (cabin) crew suspect that smoke/fumes are coming from any of the following: The avionics, The air conditioning, The cabin equipment. Requested by the SMOKE AVNCS VENT SMOKE procedure. There is a smell of smoke/fumes in the cockpit. — FCOM PRO-ABN-SMOKE

[!warning]- A smell triggers the procedure — there need not be an ECAM

The SMOKE/FUMES procedure does not require an ECAM warning — the crew applies it the moment they suspect smoke or smell fumes. Unlike other ECAM procedures (which wait for a trigger), this is subjective. Why: smoke detection covers limited areas (avionics, cargo, lavatory, crew rest, VCC, IFE) — the general cabin / cockpit have no dedicated detector, so the crew detects by smell / sight. The subjective suspicion is the trigger condition.

3. Three-layer structure

   1. IMMEDIATE ACTIONS (regardless of source)
        LAND ASAP (red); CREW OXY MASKS USE / 100% / EMERG; verify crew communication
   2. BOXED ITEMS ("at any time" decisions)
        if smoke is the greatest threat → REMOVAL OF SMOKE; if out of control → ELEC EMER CONFIG
   3. SOURCE BRANCHES (diagnose + isolate)
        AIR COND suspected / CABIN EQPT suspected / AVNCS-ELECTRICAL suspected

4. IMMEDIATE ACTIONS

LAND ASAP. APPLY IMMEDIATELY. CREW OXY MASKS (if required) ... USE / 100% / EMERG. — FCOM PRO-ABN-SMOKE

[!important]- LAND ASAP red vs amber — a major distinction

The QRH LAND ASAP is two colours: red = "use the nearest suitable airport at which a safe landing can be made" — not deferrable, flight safety is at risk; amber = "consider the urgency of the situation" — deferrable to a suitable airport. SMOKE/FUMES = red LAND ASAP — do not try to fly back to base; land at the nearest suitable airport.

[!note]- CREW OXY MASKS — three settings (N / 100% / EMERG)

N (NORMAL): a diluted mix of cabin air + O₂ (saves O₂). 100%: pure O₂ (suspected hypoxia / dense smoke). EMERG: high-pressure O₂ (positive pressure in the mask — smoke leaking into the mask / extreme). For smoke/fumes, at least 100 % (against inhaling smoke); severe → EMERG (mask positive pressure prevents external leak-in).

5. AIR COND branch

   If AIR COND smoke/fumes suspected:
     APU BLEED ... OFF
     VENTILATION EXTRACT ... AUTO   (note: in OVRD a single pack may not hold cabin pressure)
     ALL CARGO ISOL VALVES ... OFF  (prevent a cargo-smoke warning triggered by cabin smoke)
     PACK 1 ... OFF                 ← switch off PACK 1 first
     If smoke continues: PACK 1 ... ON; PACK 2 ... OFF
       If it persists: PACK 2 ... ON; VENTILATION EXTRACT ... OVRD; REMOVAL OF SMOKE ... CONSIDER

[!warning]- Switch off PACK 1 first, then PACK 2 — not both at once

The intuition is "smoke from the air-conditioning → switch off both packs". The FCOM instead: switch off PACK 1 (watch the smoke); if it does not clear, restore PACK 1 + switch off PACK 2 (watch again); only if it still persists, both back on + VENTILATION EXTRACT OVRD. This is side-by-side elimination: PACK 1 off clears it → the source is pack 1 (or that side's bleed); PACK 1 off but smoke remains → not pack 1, restore it + try pack 2; both tried → not a single-pack source → escalate. You cannot switch off both at once (the cabin loses ventilation — bearable briefly but not in sustained flight — and you cannot localise the side). Elimination, not a blanket action.

[!important]- ALL CARGO ISOL VALVES OFF — the hidden purpose

"To prevent a cargo smoke/fumes warning from being triggered due to cabin smoke/fumes." The cargo ventilation draws cabin air (ata-21-16) — cabin smoke → into the cargo → the cargo detector triggers CARGO SMOKE → a false alarm. Closing the CARGO ISOL VALVES blocks that path. The engineer foresaw the secondary-trigger problem: "the source is the cabin, do not be misled by a cargo false alarm".

[!note]- VENTILATION EXTRACT AUTO vs OVRD

AUTO = the extract fan normal (speed by cabin pressure); OVRD = forced full speed. The AIR COND branch starts AUTO (the default); only after both packs are tried does it escalate to OVRD (forced extraction to speed smoke removal). "In OVRD a single pack may not hold cabin pressure" — OVRD forces high extraction → high cabin flow → if only one pack is working (the other under test), the single-pack flow cannot balance it → cabin pressure lost.

6. CABIN EQPT branch

   If CABIN EQPT smoke/fumes suspected:
     PAX SYS ... OFF
     If smoke continues:
       EMER EXIT LT ... ON   (recover minimum cabin lighting when COMMERCIAL is OFF)
       COMMERCIAL ... OFF
       SMOKE/FUMES DISSIPATION ... CHECK; FAULTY EQPT ... SEARCH / ISOLATE

[!tip]- PAX SYS vs COMMERCIAL — different scopes of cabin power

PAX SYS = passenger entertainment + reading lights + cabin signs + service calls. COMMERCIAL = all cabin commercial power (incl. PAX SYS + galleys / ovens / coffee makers / IFE / Wi-Fi). EMER EXIT LT = the emergency-exit sign lights (independent supply). The cabin-source search goes small-to-large: PAX SYS first (the commonest cabin source) → COMMERCIAL (all commercial power) → with EMER EXIT LT ON (keep the signs visible, no total cabin blackout).

7. AVNCS / ELECTRICAL branch

   If the source cannot be determined and persists, or AVNCS/ELECTRICAL suspected:
     shed the AC BUS on one side, then the other; reconnect a clearly-uninvolved side.
   Shed AC BUS 1:
     GEN 2 ... CHECK ON; ECAM/ND SEL ... F/O; ELEC/AC page ... SELECT
     BUS TIE ... OFF        (the BUS TIE OFF caution after 5 s)
     AC ESS FEED ... ALTN   (avoids AP/A-THR disconnection during electrical transients)
     GEN 1 ... OFF          (the ECAM SD is lost)
     SMOKE/FUMES DISSIPATION ... CHECK
   If smoke continues: GEN 1 ... ON; AC ESS FEED ... NORM; ECAM/ND SEL ... NORM → shed AC BUS 2

[!warning]- AC ESS FEED → ALTN to prevent an AP/A-THR disconnect

Shedding AC BUS 1 (GEN 1 OFF) involves electrical transients that briefly affect the AC ESS BUS → with AC ESS FEED in NORM, a transient would trip the AP / A-THR off (the protection logic). Pre-empt it: AC ESS FEED → ALTN first (a backup feed path unaffected by the BUS TIE OFF transient) → the AP / A-THR stay engaged. After the shed + smoke check, restore AC ESS FEED to NORM. An ATA 21 + ATA 24 cross-system design protecting both the smoke search and the aircraft control. (AC BUS 1 first by convention — its loss also drops the ECAM SD, so the pilot uses the F/O ND with the ELEC page.)

8. ELEC EMER CONFIG — the extreme

   TO SET ELEC EMER CONFIG: EMER ELEC PWR ... MAN ON; when EMER GEN available: GEN 1/2 + APU GEN ... OFF
   If SMOKE AVNCS VENT SMOKE not triggered:
     apply ELEC EMER CONFIG, BUT DO NOT RESET GEN, EVEN IF REQUESTED BY ECAM.
   At 3 min before landing or 2000 ft AAL:
     ATT HDG sw ... F/O ON 3; ALL GENs ... ON   (recover normal braking + flight-control law)
   When stopped: ALL GENs ... OFF

[!important]- Restore the generators 3 min before landing / 2000 ft AAL — why

ELEC EMER CONFIG (RAT + emergency generator) keeps the aircraft flying but degrades much: SPD BRK DO NOT USE, MAX SPEED 330/.82, no normal braking, ALTN LAW, many INOP. Landing needs normal braking + the normal flight-control law — but staying in ELEC EMER CONFIG to landing → poor braking + degraded law → dangerous. Restoring the generators 3 min / 2000 ft AAL keeps the minimum-possible time in the normal configuration for landing (the smoke source may reactivate, but the time to landing is short); after landing, ALL GENs OFF cuts the smoke source at once. An engineer's trade-off of the smoke source against the landing performance.

[!note]- "switch the F/O side on IR 3" — a detail

IR 3 is the standby inertial reference (ATA 34). In ELEC EMER CONFIG, IR 3 survives; restoring the generators restarts IR 2 unaligned → the PFD 2 / ND 2 data may be wrong. Switch the F/O side to IR 3 first, then restore the generators — avoiding bad PFD 2 data. A hidden ATA 31/34 link inside the ATA 21 smoke procedure.

9. REMOVAL OF SMOKE (the boxed item) & detector faults

[!important]- "At any time" escalation

If at any time the smoke becomes the greatest threat or the situation is out of control, the pilot can jump to the REMOVAL OF SMOKE/FUMES sub-procedure — a rapid depressurisation to vent the smoke (the pilot's decision) + maximum ventilation. A pilot-initiated escalation, no ECAM trigger needed. SMOKE/FUMES is not a single line — it is a branching decision tree + escalation actions.

[!warning]- Real smoke vs a detector fault

ECAM	Meaning	Procedure
SMOKE/FUMES (QRH)	real smoke, crew suspects	this QRH procedure
SMOKE DET FAULT	the smoke-detection system failed (cannot detect)	not a fire — protection lost
SMOKE AVIONICS DET FAULT	avionics detection failed	same
SMOKE LAVATORY / FLT-CAB REST DET FAULT	that detection failed	same

A detector fault does not use the QRH SMOKE/FUMES procedure — apply its own crew-awareness procedure + enhanced manual watch (the automatic detection is lost). SMOKE DET FAULT may switch several ATA 21 items OFF (BULK AVNCS / PAX SYS / FWD+AFT+BULK ISOL VALVE) to guard against a hidden source with detection lost — but it remains L2. The L3 QRH procedure is only for a subjective suspicion or a real SMOKE AVNCS VENT SMOKE warning.

10. Decision tree & the key ATA 21 components

   smell smoke OR ECAM SMOKE/FUMES/AVNCS SMOKE
     IMMEDIATE: CREW OXY MASKS; verify comms; LAND ASAP (red) → nearest suitable
     judge the source (a specific smell may point to a specific source; where is the smoke?; a dedicated ECAM?)
     branch:
       AIR COND  → APU BLEED OFF / VENT EXTRACT AUTO / CARGO ISOL OFF / PACK 1 then PACK 2
       CABIN EQPT → PAX SYS OFF / COMMERCIAL OFF
       AVNCS-ELEC → shed AC BUS 1 then 2
     escalate if persisting: VENTILATION EXTRACT OVRD / ELEC EMER CONFIG / REMOVAL OF SMOKE
     approach: if ELEC EMER CONFIG, restore GEN 3 min / 2000 ft AAL; after landing ALL GENs OFF

SMOKE/FUMES spans ATA 21 / 23 / 24 / 26 / 33 — the most cross-system ATA 21 procedure.

Self-test

[!note]- Q1. Do you apply SMOKE/FUMES when you smell smoke but there is no ECAM?

Yes. The procedure does not require an ECAM — a suspicion or a cockpit smell is itself the trigger. The general cabin / cockpit have no dedicated detector, so the crew detects by smell/sight; the subjective suspicion is the trigger condition. Don the crew oxygen masks immediately (a fumes source may be toxic).

[!note]- Q2. Why switch off PACK 1 first in the AIR COND branch, not both packs at once?

Side-by-side elimination: PACK 1 off + smoke clears → the source is pack 1's side; PACK 1 off but smoke remains → restore PACK 1 + switch off PACK 2 → watch; both tried + smoke remains → not a single-pack source → escalate to VENTILATION EXTRACT OVRD. Switching off both loses cabin ventilation (not sustainable in flight) and cannot localise the side. Elimination, not a blanket action.

[!note]- Q3. Why set AC ESS FEED to ALTN when shedding AC BUS 1?

To prevent an AP/A-THR disconnect. The BUS TIE OFF + GEN 1 OFF sequence creates electrical transients; with AC ESS FEED in NORM, a transient trips the AP/A-THR off (protection logic). AC ESS FEED → ALTN (a backup feed unaffected by the transient) keeps the AP/A-THR engaged. Restore NORM after the shed. An ATA 21 + ATA 24 cross-system protection of the aircraft control.

[!note]- Q4. In ELEC EMER CONFIG, why restore the generators 3 min before landing / 2000 ft AAL?

A trade-off of the smoke source against the landing performance. ELEC EMER CONFIG degrades much (no normal braking / ALTN LAW / SPD BRK DO NOT USE); landing needs normal braking + the normal control law, but restoring the generators may reactivate the smoke source. 3 min / 2000 ft AAL keeps the minimum-possible time in the normal configuration for landing (the source may reactivate, but the time to landing is short); after landing, ALL GENs OFF cuts the source.

[!note]- Q5. ECAM SMOKE DET FAULT but no smell — apply the SMOKE/FUMES procedure?

No. SMOKE DET FAULT = the smoke-detection system has failed, not real smoke. Apply its own procedure (some ATA 21 items OFF to guard against a hidden source with detection lost) + enhanced manual watch — not the QRH SMOKE/FUMES procedure. The L3 procedure is only for a subjective suspicion or a real SMOKE AVNCS VENT SMOKE warning.

Key takeaways

Common misconceptions

Scope — what this article covers and defers

References

A330 specifics per FCOM PRO-ABN-SMOKE (the SMOKE/FUMES/AVNCS SMOKE procedure — the apply-on-suspicion/smell condition, the immediate actions with the red LAND ASAP and the CREW OXY MASKS USE/100%/EMERG, the AIR COND branch with APU BLEED OFF / VENTILATION EXTRACT AUTO / ALL CARGO ISOL VALVES OFF and the PACK 1-then-PACK 2 elimination, the CABIN EQPT branch with PAX SYS / COMMERCIAL / EMER EXIT LT, the AVNCS-ELECTRICAL branch with the AC BUS shedding and the AC ESS FEED → ALTN AP/A-THR protection, the ELEC EMER CONFIG with the 3 min / 2000 ft AAL generator restore, the REMOVAL OF SMOKE boxed item, and the SMOKE DET FAULT detector-fault distinction). The three-layer teaching structure, the side-by-side elimination rationale, and the smoke-vs-landing-performance trade-off are integrative syntheses. The cross-system steps (AC BUS / ELEC EMER CONFIG / IR 3) are presented as they appear in the ATA 21 procedure with the detail deferred to ATA 24 / 34. All engineering detail is from the A330 knowledge base; the procedures are presented generically without operator-specific SOP, no cross-type comparison is made, and no fleet tail numbers appear.

Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.